Scotch whisky is spelt without an e, American and Irish whiskeys are spelt with an e.

Now back to beer .....

Actually not quite as simple as that!

The spelling whisky (plural: whiskies) is generally used in Canada, Japan, Scotland, and Wales, while whiskey (plural: whiskeys) is more common in Ireland and the United States. The usage is not always consistent – for example, some prominent American brands, such as George Dickel, Maker's Mark, and Old Forester (which are all made by different companies), use the 'whisky' spelling on their labels, and the US legal Standards of Identity for Distilled Spirits document also uses the 'whisky' spelling.
"Scotch" is the internationally recognized term for "Scotch whisky". It is rarely used in Scotland, where the drink is called simply "whisky"."Proud to be born and bred in Croydon"